how to loop a button's functions every "X" minutes?

using System;
using System.Windows.Forms;

namespace Repeat
{
    static class Program
    {
        [STAThread]
        static void Main()
        {
            // Create a test Form with Buttons and a Textbox to enter the repetition count
            Form form = new Form();
            Button buttonStart = new Button();
            buttonStart.Text = "Start";
            buttonStart.Dock = DockStyle.Top;
            Button buttonStop = new Button();
            buttonStop.Text = "Stop";
            buttonStop.Dock = DockStyle.Top;
            TextBox textbox = new TextBox();
            textbox.Dock = DockStyle.Top;
            form.Controls.Add(buttonStop);
            form.Controls.Add(buttonStart);
            form.Controls.Add(textbox);

            // Create a timer
            Timer timer = new Timer();
            timer.Interval = 60000; // set the timer interval to one minute
 
            int iRepetitionCount = 0; // Number of remainig repetitions

            // Add event handlers for the button Click-Events

            buttonStart.Click += delegate(object sender, EventArgs e)
            {
                // Restarting also stops the timer
                timer.Stop();

                if (String.IsNullOrWhiteSpace(textbox.Text)) // Textbox empty?
                {
                    // Just call the function once
                    TheFunction();
                }
                else
                {
                    // Try to get the entered repetition value
                    iRepetitionCount = 0; // reset
                    if (!Int32.TryParse(textbox.Text, out iRepetitionCount))
                    {
                        MessageBox.Show("Invalid repetition count");// The entered text could not be converted to an integer
                        return;
                    }

                    // Call the function now 
                    TheFunction();
                    iRepetitionCount--;  // Decrement the repetition counter
                    // ... and start the timer (on timer.Tick the Function will be called again)
                    timer.Start();
                }
            };

            buttonStop.Click += delegate(object sender, EventArgs e)
            {
                // Stop the repetition timer
                timer.Stop();
            };

            // Add event handlers for the timer Tick-Events

            timer.Tick += delegate(object sender, EventArgs e)
            {
                if (iRepetitionCount <= 0) // no more repetitions?
                {
                    timer.Stop(); // stop the timer now
                }
                else
                {
                    iRepetitionCount--; // Decrement the repetition counter
                    TheFunction(); // Call the function
                }
            };

            // Run the form
            Application.Run(form);
        }

        static void TheFunction()
        {
            MessageBox.Show("I was called at " + DateTime.Now.ToString());
        }
    }
}